The Centre for SMART has developed the world’s first comprehensive system for separating and recovering useful materials from old footwear.
Successful trials are able to granulate and segregate leather, plastic foams and rubber so that they can be re-used in products ranging from rubber playground surfacing to new shoes.
'Footwear is incredibly difficult to recycle as it can contain up to forty different types of material, many of which are stitched or glued together', says Professor Shahin Rahimifard, who led the project. 'In our process, the first, manual step is to pre-sort shoes into broad types, such as trainers, and to recover metals, such as eyelets. Next the shoes are automatically shredded and granulated, with the granules automatically separated into four waste streams: leather, foams, rubber and other material.'
Collaboration is also underway with major footwear manufacturers to explore how shoes could be designed differently in the future to make them easier to recycle. The SMART team has already developed a computerised tool that advises footwear designers on materials selection and helps them explore whether particular combinations of materials would make recycling harder or easier.
These are important first steps down a path to help keep at least some of the 20 billion pairs of shoes produced globally out of landfill.